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MDEV-22491 Support mariadb-check and CHECK TABLE with SEQUENCE

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The check go through the following steps:

1. Run check on the underlying engine. If not ok, then return.
2. Check that there's only one row in the table, and
   2.1 warn if more than one row
   2.2 return HA_ADMIN_CORRUPT if fewer than one row (i.e. 0 rows)
3. If the sequence is not initialised (e.g. after an ALTER TABLE ...
   SEQUENCE=1), initialise the sequence by reading the sequence
   metadata from the table. This will also flush the next_free_value,
   i.e. set it to the next not cached value (SEQUENCE::reserved_until)
4. Check that the sequence metadata is valid, i.e. nothing out of
   order e.g. minvalue < maxvalue etc. If invalid it reports
   HA_ERR_SEQUENCE_INVALID_DATA
5. Check that the sequence has not been exhausted. It reports
   ER_SEQUENCE_RUN_OUT as a warning if and only if a SELECT NEXTVAL
   would do so

Limitations:

1. The check is independent of flags, so the vanilla check is the same
   as CHECK ... EXTENDED or CHECK ... FOR UPGRADE etc.
2. When the check discovers invalid metadata from the table,
   subsequent SELECT NEXTVAL will carry on (or fail) without this
   piece of knowledge, independent of the CHECK. This is to ensure
   consistency, i.e. CHECK does not modify behaviour of SELECT, and if
   anything it makes more sense that SELECT reports
   HA_ERR_SEQUENCE_INVALID_DATA in this case, regardless of prior
   CHECK
This commit is contained in:
Yuchen Pei
2025-05-02 10:44:45 +10:00
parent 26ea37be5d
commit d52ddae57b
10 changed files with 333 additions and 12 deletions
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44
sql/ha_sequence.cc
View File

@@ -420,6 +420,50 @@ void ha_sequence::print_error(int error, myf errflag)
DBUG_VOID_RETURN;
}
int ha_sequence::check(THD* thd, HA_CHECK_OPT* check_opt)
{
DBUG_ENTER("ha_sequence::check");
/* Check the underlying engine */
if (int ret= file->check(thd, check_opt))
DBUG_RETURN(ret);
/* Check number of rows */
if ((file->table_flags() & HA_STATS_RECORDS_IS_EXACT))
{
if (file->stats.records > 1)
push_warning(thd, Sql_condition::WARN_LEVEL_WARN,
ER_SEQUENCE_TABLE_HAS_TOO_MANY_ROWS,
ER_THD(thd, ER_SEQUENCE_TABLE_HAS_TOO_MANY_ROWS));
else if (file->stats.records == 0)
{
my_error(ER_SEQUENCE_TABLE_HAS_TOO_FEW_ROWS, MYF(0));
DBUG_RETURN(HA_ADMIN_CORRUPT);
}
}
/*
Initialise the sequence from the table if needed.
*/
if (sequence->initialized == SEQUENCE::SEQ_UNINTIALIZED)
{
if (sequence->read_stored_values(table))
DBUG_RETURN(HA_ADMIN_FAILED);
else
sequence->initialized= SEQUENCE::SEQ_READY_TO_USE;
}
DBUG_ASSERT(sequence->initialized == SEQUENCE::SEQ_READY_TO_USE);
/* Check and adjust sequence state */
if (sequence->check_and_adjust(thd, false, /*adjust_next=*/false))
{
print_error(HA_ERR_SEQUENCE_INVALID_DATA, MYF(0));
DBUG_RETURN(HA_ADMIN_CORRUPT);
}
/* Check value not exhausted */
if (sequence->has_run_out())
push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
ER_SEQUENCE_RUN_OUT, ER_THD(thd, ER_SEQUENCE_RUN_OUT),
table->s->db.str, table->s->table_name.str);
DBUG_RETURN(0);
}
/*****************************************************************************
Sequence plugin interface
*****************************************************************************/